I didn't see anyone recommend IAB. It will show you exactly what you need. But a basic standard is CPU plus 3 cards. Then pb4. Then up.to 8 cards then new rack and pb4. But again IAB tool from Rockwell will help you

The easiest way to figure it out is use the Integrated Architecture Builder software from Rockwell. You can build the rack in the software and placed the cards in it and it will tell you power supply loading, card placement requirements, and the number of allowable cards. There are several special case requirements for some 1769 cards, and its hard to remember them all. The software is free and takes out all the guesswork.

I didn't see anyone recommend IAB. It will show you exactly what you need. But a basic standard is CPU plus 3 cards. Then pb4. Then up.to 8 cards then new rack and pb4. But again IAB tool from Rockwell will help you

...Of course, all of this is academic if you use Rockwell's IAB software, which will work all this out for you and tell you exactly what you need. Though it's still useful to know, because in some cases IAB might tell you that you need another rack with an expansion cable and PS for a particular configuration, but if you understand the limitations, you might be able to rearrange your rack to put the low distance rating modules closer to the PS and get it to work with a single rack.

Yes, for my first post I was in the process of explaining the advantages of using IAB to help take the guess work out of all this when I noticed ASF had since mentioned it. I was even going to look for and link an old post where I think I outlined using it before? But there was no real need as it turned out. So credit to ASF where it is most definitely due here.

I suppose it's one of the disadvantages of composing relatively longer posts. Not everyone has the time or patience to read all of their contents. Or they do but skip through them a bit too quickly.

G.

__________________
"A little nonsense now and then is relished by the wisest men".